The present invention relates to mixing valves. More particularly it relates to thermostatic mixing valves with improved access to check valves and filter screens and improved settings for comfort temperatures.
Thermostatic mixing valves can provide a source of water having a desired temperature and can maintain the desired water temperature substantially constant once set. Such devices are well known in the art. See e.g. U.S. Pat. No. 6,279,604 and U.S. patent application publication 2004/0000594. Typically, the desired water temperature is obtained by controlling the relative proportions of hot and cold water admitted to a mixing chamber and adjusting the relative proportions to maintain the desired water temperature substantially constant.
To prevent the temperature from being set at a temperature that risks scalding, a temperature stop is typically provided on the mixing valve. The valves often also include a method for setting a lower “comfort” level.
To prevent cross flow between the hot and cold input lines, check valves can be provided between the hot and cold water supplies and the mixer valves. Also, screens can be provided to avoid debris from clogging the valve interior.
While thermostatic mixing valves are known in the art, these known devices suffer from a number of disadvantages. For example, in some prior art devices, when the comfort level is selected, the maximum temperature selection is determined by a fixed increment therefrom. In any event, to properly maintain the valve, the check valves and associated screens need to be periodically cleaned. This process can require the use of a number of tools, requires some skill, and can be time consuming.
Therefore, there remains a need for an improved thermostatic mixer valve in which the check valves and screens are easily and quickly cleaned. Furthermore, there remains a need for an improved thermostatic mixer valve that mechanically provides a user selectable comfort level independent of the maximum temperature level.